To maintain stability of an automotive vehicle, particularly at high speed, a wing-shaped spoiler has often been provided at a rear part of the vehicle (see Japanese Utility Model Examined Publication No. 1-15578). To meet the demands of various designs of the vehicles, there have been greater demands for various designs of spoilers.
However, in spoilers in which a stay portion is formed integral with a spoiler body through blow molding, it is difficult to obtain an under-cut shape of the stay portion, i.e., a shape wherein the stay portion diverges toward its vehicle-mounting portion.
For this reason, in order to ensure a sufficient mounting strength relative to the vehicle body, the freedom of design is limited to one wherein both ends of the spoiler body are fixed to the vehicle body or the stay portion is enlarged in size.